A014486-indices of the plane binary trees AND plane general trees whose left subtree is just a stick: \. thus corresponding to the parenthesizations whose first element (of the top-level list) is an empty parenthesization: ().

This sequence is induced by the 'flipped form' of the function 'list': (define (flippedlist x) (cons '() x)) when it acts on symbolless S-expressions encoded by A014486/A063171.